U.S. patent application number 14/379782 was filed with the patent office on 2015-01-15 for composition comprising an alkoxylated amine compound and a carboxylic acid compound, use thereof in water in oil emulsions and process using the composition as or as part of a drilling fluid.
The applicant listed for this patent is Sasol Olefins & Surfactants GmbH. Invention is credited to Ludger Bosing, Heinz Napierala.
Application Number | 20150014062 14/379782 |
Document ID | / |
Family ID | 47747553 |
Filed Date | 2015-01-15 |
United States Patent
Application |
20150014062 |
Kind Code |
A1 |
Napierala; Heinz ; et
al. |
January 15, 2015 |
Composition Comprising an Alkoxylated Amine Compound and a
Carboxylic Acid Compound, use thereof in Water in Oil Emulsions and
Process Using the Composition as or as Part of a Drilling Fluid
Abstract
The object of the present invention is a composition comprising
amine compound and carboxylic acid compounds, wherein at least the
amine compounds are alkoxylated, use thereof as a drilling fluid,
and a method for using the drilling fluid
Inventors: |
Napierala; Heinz; (Herten,
DE) ; Bosing; Ludger; (Dorsten, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sasol Olefins & Surfactants GmbH |
Hamburg |
|
DE |
|
|
Family ID: |
47747553 |
Appl. No.: |
14/379782 |
Filed: |
February 20, 2013 |
PCT Filed: |
February 20, 2013 |
PCT NO: |
PCT/EP2013/000487 |
371 Date: |
August 20, 2014 |
Current U.S.
Class: |
175/66 ; 175/65;
507/117; 507/133; 507/136; 585/4 |
Current CPC
Class: |
E21B 21/065 20130101;
E21B 21/012 20130101; C10G 1/04 20130101; C09K 8/28 20130101; C09K
8/36 20130101 |
Class at
Publication: |
175/66 ; 585/4;
507/136; 507/133; 507/117; 175/65 |
International
Class: |
C09K 8/36 20060101
C09K008/36; E21B 21/01 20060101 E21B021/01; E21B 21/06 20060101
E21B021/06; C10G 1/04 20060101 C10G001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 20, 2012 |
DE |
102012003224.2 |
Claims
1. A composition comprising: (A) at least one of primary,
secondary, tertiary alkoxylated amine compounds, or mixture thereof
and (B) at least one of carboxylic acid compounds selected from at
least one of polyalkene glycol ether carboxylic acids of a
monoalcohol, poly-alkylene glycol ether carboxylic acids of a
polyol, or mixtures thereof (C) an oil that is liquid at least at
25.degree. C., and (F) water, wherein the composition further
comprises salts dissolved in the water (F) in a concentration of
greater than 1% by wt. an the composition is a
water-in-oil-emulsion wherein the oil (C) forms the continuous
phase and the water (F) forms the dispersed phase.
2. The composition according to claim 1, wherein the polyalkylene
glycol ether carboxylic acids of a monoalcohol and/or a polyol have
the general formula R.sup.3--[--O--(Z).sub.p-E].sub.y wherein
R.sup.3 stands for a hydrocarbon radical with 1 to 24 hydrocarbon
atoms, Z stands for alkoxylate groups --CH2-CHR2-O-- or
--CHR2-CH2-O-- which may or may not be different for each p,
R.sup.2 stands for H, a methyl group or an ethyl group, which may
or may not be different for each p, E stands for --CH.sub.2--COOH,
p stands for average numerical values from greater than 0 to 15 and
y is 1 in the case of a monoalcohol, and 2, 3, 4, 5 or 6 in the
case of a polyol.
3. The composition according to claim 1, wherein the amine
compounds have the following general formula
R.sup.1--N(--X.sub.nH)(--X.sub.mH) or (R.sup.1--)(R4-)N(--X.sub.nH)
in which R.sup.1, R.sup.4 each stand for a hydrocarbon radical with
4 to 24 hydrocarbon atoms, X stands for CH.sub.2--CHR.sup.2--O-- or
--CHR.sup.2--CH.sub.2--O--, and may or may not be different for
each m and n, R.sup.2 stands for H, a methyl group or an ethyl
group and may or may not be different for each m and n, n and m
independently of one another stand for average numerical values
from greater than 0 to 30, and independently thereof the sum of n
plus m is equal to a value from greater than 0.5 to 30.
4. The composition according to claim 3, wherein for
R.sup.1--N(--X.sub.nH)(--X.sub.mH) n+m+p is between 2 and 8 and for
(R.sup.1--)(R.sup.4--)N(--X.sub.nH) n+p is between 2 and 8.
5. The composition according to claim 1, wherein the amine compound
is an alkoxylated imidazol, alkoxylated piperazine, or mixtures
thereof.
6. The composition according to claim 1, wherein the oil (C) has a
flashpoint higher than 60.degree. C. and which is measured at
temperatures of higher than 60.degree. C. up to 70.degree. C.
according to DIN 51755 and at temperatures higher than 70.degree.
C. according to EN ISO 2719.
7. The composition according to claim 1, wherein the oil (C)
comprises hydrocarbons, esters, alcohols or mixtures thereof.
8. The composition according to claim 1, wherein the composition
further comprises salts dissolved in the water (F) in a
concentration greater than 5% by wt.
9. The composition according to claim 1, wherein the composition
further comprises (D) at least one thickening agent for thickening
the oil, and (E) at least one additive selected from the group
consisting of alkaline and earth alkaline halides, sulphates,
carbonates, hydrogencarbonates, hydroxides, iron oxides, and
mixtures thereof.
10. The composition according to claim 9 wherein (D) the thickening
agent is a clay selected from bentonite, hectorite, attapulgite and
mixtures thereof.
11. The composition according to claim 9, wherein the additive (E)
is calcium carbonate, barium sulphate, iron-III-oxide or mixtures
thereof.
12. The composition according to claim 1, wherein the composition
has a pH value from 3 to 11.
13. The composition according to claim 9, wherein the composition
comprises independently of each other 0.05 to 10% by wt. amine
compound (A) and carboxylic acid compound (B), (C) 5% by wt. to 50%
by wt. the oil, (D) 0.05% by wt. to 5% by wt. the thickening agent,
(E) 1% by wt. to 60% by wt. the additive, (F) 2% by wt. to 50% by
wt. water.
14. The composition according to claim 9, comprising the amine
compound (A) and the carboxylic acid compound (B) in molar ration
from 1:1.5 to 0.5 to 1, each related to the number of amine and
carboxylic acid functional groups in (A) and (B).
15. A method for drilling an earth borehole, comprising the steps
of introducing a drilling fluid into the earth borehole during the
drilling operation, said drilling fluid comprising (A) at least one
of the primary, secondary, tertiary, alkoxylated amine compounds or
mixtures thereof, (B) at least one of carboxylic acid compounds
selected from poly-alkylene glycol ether carboxylic acids of a
monoalcohol, poly-alkylene glycol ether carboxylic acids of a
polyol, or mixtures thereof, (C) an oil that is liquid at least at
25.degree. C., and (F) water.
16. The method according to claim 15, further including the step of
extracting the drilling fluid including drilled material,
separating the drilled material out of the drilling fluid, and
returning the drilling fluid to the earth borehole minus the
separated drilled material.
17. The method according to claim 15 further including the step of
extracting the drilling fluid including drilled material, bringing
at least a portion of the drilling fluid into contact with one of a
base or an acid to break the water-in-oil-emulsion by setting a pH
value of lower than 3 or higher than 11, respectively to obtain an
inverted emulsion being an oil-in-water emulsion.
18. The method according to claim 17 including the step of exposing
the inverted emulsion being an oil-in-water emulsion to one of a
base or acid thus setting a pH value from 3 to 11, respectively to
obtain a water-in-oil emulsion.
19. The method according to claim 16, further including the step of
bringing the drilled material into contact with one of a base or
acid to break the water-in-oil emulsion by setting a pH value of
lower than 3 or higher than 11, respectively, wherein an
oil-in-water emulsion flushing fluid and a drilled material minus
the oil are obtained.
20. The method of claim 15, wherein said earth borehole comprises
one of an oil and gas well, a geothermal well or a water well.
21. (canceled)
22. A method of improving flow of heavy hydrocarbons comprising
introducing a composition comprising: (A) one or more primary,
secondary or tertiary alkoxylated amine compounds and (B) one or
more carboxylic acid compounds selected from one or more members of
the group of polyalkylene glycol ether carboxylic acids of a
monoalcohol and poly-alkylene glycol ether carboxylic acids of a
polyol, (F) water, wherein the composition further comprises salts
dissolved in the water (F) in a concentration of greater than 1% by
wt. and the composition is a water-in-oil-emulsion wherein the oil
(C) forms the continuous phase and the water (F) forms the
dispersed phase, into heavy crude oils or extra heavy crude oils to
form water-in-oil emulsions with reduced viscosity.
23. A method of forming a water-in-oil emulsion comprising:
introducing a composition comprising: (A) one or more primary,
secondary, or tertiary alkoxylated amine compounds and (B) one or
more carboxylic acid compounds selected from one or more members of
the group of polyalkylene glycol ether carboxylic acids of a
monoalcohol and poly-alkylene glycol ether carboxylic acids of a
polyol, into a mixture of water and oil.
24. The composition according to claim 3, wherein R.sup.1 and
R.sup.4 form at least one ring with a total of 4 to 24 hydrocarbon
atoms.
25. The composition according to claim 6, wherein said flashpoint
according to DIN 51755 is greater than 70.degree. C.
26. The composition according to claim 7, wherein said hydrocarbons
are aliphatic or cycloaliphatic and the esters are ethyl and/or
methyl (C12 to C22) fatty acid esters.
27. The composition according to claim 8, wherein said salts are in
a concentration greater than 15% by wt.
28. The composition according to claim 8, wherein said salts are in
a concentration greater than 20% by wt.
29. The composition according to claim 9, wherein said thickening
agent is selected from the group consisting of clays, polymers,
alumina, silica, and mixtures thereof.
30. The composition according to claim 10, wherein the thickening
agent is an organically modified clay.
31. The composition according to claim 10, wherein said clay is
organically modified with a fatty amine.
32. The composition according to claim 11, wherein said additive
may be in the form of minerals.
33. The composition according to claim 12, wherein said pH is from
4 to 10.
34. The composition according to claim 13, wherein the composition
comprises 0.1% by wt. to 5% by wt. (A) and (B).
35. The composition according to claim 13, wherein (C) is present
in an amount of from 10% by wt. to 20% by wt.
36. The composition according to claim 13, wherein (D) is present
in an amount of from 0.5% by wt. to 3% by wt.
37. The composition according to claim 13, wherein (E) is present
in an amount of from 30% by wt. to 50% by wt.
38. The composition according to claim 13, wherein (F) is present
in an amount of from 2% by wt. to 40% by wt.
39. The composition according to claim 13, wherein (F) is present
in an amount of from 2% by wt. to 30% by wt.
40. The composition according to claim 14, wherein aid molar ration
is from 1:1.2 to 0.8 to 1.
41. The method according to claim 15, wherein said drilling fluid
further comprises: (D) at least one thickening agent for thickening
the oil, (E) at least one additive selected from the group
consisting of alkaline and earth alkaline halides, sulphates,
carbonates, hydrogencarbonates, hydroxides, iron oxides, and
mixtures thereof.
42. The method according to claim 15, wherein said drilling fluid
further comprises: (E) at least one additive selected from the
group consisting of alkaline and earth alkaline halides, sulphates,
carbonates, hydrogencarbonates, hydroxides, iron oxides, and
mixtures thereof.
43. The method according to claim 42, wherein said drilling fluid
further comprises: (D) at least one thickening agent for thickening
the oil.
44. The method according to claim 16, wherein the drilling fluid
minus the separated drilled material is returned to the earth
borehole after the addition of at least one of components (A) to
(F).
45. The method according to claim 17, wherein drilled material is
removed prior to bringing said drilling fluid into contact with
said base or acid.
Description
[0001] The present invention relates to a composition containing
amine and carboxylic acid compounds as oil in water emulsifier
system, the use thereof in oil based drilling fluids and a process
using the drilling fluids.
RELATED ART
[0002] A drilling fluid also named drilling mud is a fluid that is
pumped through a drilled hole while drilling is being carried out
in order to ease the drilling process. The various functions of a
drilling fluid include the removal of drilled material below the
drill head, transporting the drilled material (cuttings) out of the
drilled hole, cooling and lubricating the drill bit, supporting the
drill pipe and the drill bit, stabilising the drill hole walls,
suspending the cuttings when circulation is stopped, providing a
liquid column to regulate the hydrostatic pressure at the surface
and preventing a "blowout". The compositions of drilling fluids are
often adapted to the properties of a given geological formation in
order to optimise a drilling process. Drilling fluids are usually
thickened, flowable systems with a water or oil base. Oil-based
drilling fluids are used for example in offshore drilling
applications and for drilling through water-sensitive layers and/or
aquifers.
[0003] Oil-based drilling fluids are generally divided into
invertible emulsion drilling fluids or conventional non-invertible
drilling fluids. Both comprise a three-phase system: a continuous
oil phase, a dispersed water phase and finely particulate solids.
These compositions are of the water-in-oil emulsion type. This
means that the aqueous phase, which constitutes the internal phase,
is finely distributed in the oil phase and the oil phase forms the
external phase.
[0004] Oil-based drilling fluids contain a base oil, which forms
the external phase, an aqueous solution containing a salt as the
internal phase, and an emulsifier or emulsifier system, which acts
on the boundary surface between the internal and external phases.
Other additives are used to stabilise and adjust the functional
characteristics.
[0005] The advantage of oil-based drilling fluids lies in its
excellent lubricating properties. These lubricating properties
enable drilling to be carried out with a considerable vertical
offset, for example, as is typical of offshore or deep water
drilling operations. In horizontal and almost horizontal wellbores,
the drill pipe lies on the lower side of the drill hole, which
results in high torques when drilling and when drawing the drill
pipe. Under these conditions, the risk of a stuck pipe is greater
when water-based drilling fluids are used. In contrast, oil-based
drilling fluids form thin, flat filter cakes on the walls of the
drilled hole and also have better characteristics than water-based
drilling fluids with regard to the swelling of chalks that are
usually present in the formation rock.
[0006] Besides their lubricating properties, important functional
characteristics of oil-based drilling fluids also include
viscosity, density and filtrate control. Filtrate control is
particularly important in unconsolidated permeable formations. In
such conditions, under hydrostatic pressure the drilled material
forms a semi-permeable, fluid-impermeable layer (for example in the
form of a filter cake) on the walls of the drilled hole, thus
reducing fluid loss, stabilising the formation pressure and
reducing that risk that the walls in the drilled hole will
collapse.
[0007] When conventional emulsifiers are used, it may be necessary
to use solvents and other surface-active additives in order to
penetrate the filter cake and alter the wettability of the filter
cake particles. Water-wetted solids are essential for a subsequent
acid wash, to dissolve or disperse the particles of the filter
cake, for example.
[0008] Amine-based emulsifiers for invert emulsion drilling fluids
that can be converted from an oil-in-water emulsion into a
water-in-oil emulsion are described in WO 98/05733.
[0009] The complexity and unpredictability of the external
conditions and the interactions of the fluid components both with
each other and with the conditions during drilling mean that a
drilling fluid must be capable of sustaining considerable loads,
which poses a challenge for developers. There is a constant need,
and thus also undiminished interest throughout the industry in new
drilling fluids that offer improved performance and at the same
time improved ecological and economical acceptance.
SUMMARY OF THE INVENTION
[0010] The object of the invention is providing a composition
comprising a water-in-oil emulsifier system for use in or as a
water-in-oil drilling fluid, hereafter also referred to in short as
a drilling fluid, a use thereof, and a process, as described in the
independent claims. Use of the emulsifier composition for
water-in-oil emulsion is also claimed. Preferred embodiments are
described in the subordinate claims or herein below.
[0011] Surprisingly, a water-in-oil emulsifier system for use in
"emulsion drilling fluids" was found. Drilling fluids based on the
emulsifier system according to the invention are notable for their
surprisingly good stability and other advantageous functional
characteristics. In particular, increased stability is observed in
respect of influences such as varying water and salt content
(salinity) as well as usability over a wide range of temperatures.
The water-in-oil emulsifier system is also suitable for other
applications, such as emulsifying water or brine in heavy oils,
lowering viscosity and improving flow properties of heavy oil
fractions.
[0012] Important application areas for the drilling fluids are
boreholes for developing oil and gas fields, geothermal bores or
water drill holes, or also drilling geo-scientific bores or mining
drill holes.
[0013] The drilling fluid according to the invention comprises an
oily, also referred to as the oil phase, an emulsifier system
comprising at least two emulsifiers, water, optionally in form of
brine, thickening agents and further additives.
[0014] An example of additives used in the composition according to
the invention are the additives for wetting, weighting agents to
increase weight or density, "fluid loss" additives to minimise
fluid loss, additives for creating an alkalinity reserve, additives
for filtration control and/or to control rheological
properties.
[0015] When the individual components of the composition according
to the invention are mixed with each other, a salt-like compound is
formed that is stable in a pH range between 4 and 10, preferably 3
and 11.
[0016] The emulsifier system contained in the composition has the
effect of lowering interfacial tension due to the positive and
negative partial charges in the molecule. The interfacial activity
can be adjusted in targeted manner by suitable selection of the
degree of alkoxylation of the components of the emulsifier
system.
[0017] By mixing the components of the emulsifier system comprising
the alkoxylated amine and the carboxylic acid compound the
appropriate HLB (Hydrophilic-Lipophilic-Balance) values can be
adjusted to yield stable invertible water-in-oil emulsion drilling
fluids.
[0018] Emulsifying properties may be further optimised by an
optional additional variation of the length of the hydrophobic
C-chain in the emulsifier components. In this way, it is possible,
for example, to produce micro-emulsions under conditions of optimal
temperature and optimal salinity. Special formulations of
surfactants with water and oil form a micro-emulsion (Winsor type
III). The occurrence of certain phases is determined by internal
(composition) and external parameters (such as temperature and
salinity). The Winsor III phase, also known as a three-phase
micro-emulsion (wherein the actual micro-emulsion is the middle
phase, coexisting with water and an oil excess phase), is notable
for extremely low interfacial tensions (IFT). This state is
therefore also described as "optimal", and the associated
parameters are described as "optimal salinity" and "optimal
temperature". The middle phase is usually of low viscosity. A lower
viscosity is desirable for transporting highly viscous heavy crude
oils or extra heavy crude oils in pipelines for example.
[0019] In this way, it is also possible to produce stable invert
emulsion drilling fluids with excellent functional characteristics
for an extremely wide range of conditions. As a rule, the degree of
alkoxylation is adjusted according to the oil and the brine
concentration used, and subsequently adjusted further as necessary
depending on the specific drilling conditions.
[0020] According to the invention, for example, the same mode of
action may be achieved with an alkoxylated dodecylamine in
combination with an ether carboxylic acid on an alkoxylated oleyl
alcohol base as with an alkoxylated oleyl amine paired with a
dodecyl alcohol-based ether carboxylic acid.
[0021] In this way, the emulsifier system according to the
invention enables variation options in adjusting the desired
emulsifier functions and adapting said functions to the required
operating characteristics of an invert emulsion drill flushing
fluid.
DETAILED DESCRIPTION OF THE INVENTION
[0022] In the following, the emulsifier system, the water-in-oil
composition and their application will be described.
[0023] The composition comprises one or more amine compounds (A)
which are one or more alkoxylated primary and/or secondary amine
compounds or mixtures thereof, and a carboxylic acid component (B).
The components (A) and (B) form the emulsifier system.
[0024] Suitable alkoxylated amine compounds according to the
invention forming component (A) are surface-active substances
derived from or based on, for example, butylamine, pentylamine,
hexylamine, octylamine, nonylamine, decylamine, undecylamine,
lauryl amine, tridecylamine, tetradecylamine, pentadecylamine,
palmityl amine, stearyl amine, arachidyl amine, behenyl amine,
lignoceryl amine as well as unsaturated or branched amines with the
same C number, for example oleyl amine, 2-ethylhexyl amine or
standard commercial or other mixtures such as coconut oil amine or
tallow oil amine. Alkoxylated dialkyl amine compounds derived from
or based on compounds containing said C-chain lengths and/or
heterocyclic, nitrogen-containing compounds, such as imidazol and
piperazine, are also suitable.
[0025] The starting amine compounds used for the preparation of the
alkoxylated amine compound forming component (A) are amines having
at least one NH valence, for example, primary and/or secondary
amines. The conversion of the amine with alkoxides is achieved by
addition with either one or more ethylene oxide, propylene oxide
and/or butylene oxide, including block and/or statistical
distributions, wherein the average numerical value of alkoxylene
units is between 0.5 and 30, preferably between 1 and 10, and most
preferred greater 1 to 6. The term "alkoxylated amines" according
to another embodiment includes alkanolamines or dialkanolamines or
in other words alkoxylated amines with only one or only two
alkoxoylate group(s).
[0026] The alkoxylated compounds consist preferably of (quasi)
statistical mixtures for example even at a degree of alkoxylation
of 0.5 (and above) there always exist compounds with a degree of
alkoxylation of two and three per molecule. In this case several
different amine compounds within components (A) with differing
degree of alkoxylation are present.
[0027] The degrees of alkoxylation given throughout this invention
are average values (number average).
[0028] The carboxylic acid compound forming component (B) of the
emulsifier system is selected from one or more members of the group
of monocarboxylic acids, polycarboxylic acids, polyalkylene glycol
ethercarboxylic acids of a monoalcohol and polyalkylene glycol
ether carboxylic acids of a polyol. Suitable carboxylic acid
compounds are for example the following carboxylic acids: lactic
acid, citric acid, oxalic acid, butyric acid, valeric acid, caproic
acid, heptanoic acid, caprylic acid, nonanoic acid, capric acid,
undecanoic acid, lauric acid, tridecanoic acid, myristic acid,
pentadecanoic acid, palmitic acid, stearic acid, behenic acid and
the branched and unsaturated types having the same C-chain length,
such as oleic acid. The monocarboxylic acids and the polycarboxylic
acids preferably contain 4 to 24, particularly 8 to 18, carbon
atoms and particularly preferred 12 to 18 carbon atoms, optionally
a hydroxy group. In particular preferred are monocarboxylic
acids.
[0029] Alcohol polyalkylene glycol ether carboxylic acids based on
for example butanol, pentanol, hexanol, heptanol, octanol, nonanol,
decanol, undecanol, lauryl alcohol, tridecanol, tetradecanol,
pentadecanol, hexadecanol, heptadecanol, octadecanol, behenyl
alcohol and the corresponding branched or unsaturated types having
the same C-chain such as oleyl alcohol or iso-octanol are also
suitable. The listed alcohols and polyalkylene glycols with
different chain lengths form the basis of the polyalkylene glycol
ether carboxylic acids (B) that are produced by polyaddition with
either ethylene oxide, propylene oxide or butylene oxide or
mixtures thereof including random or block structures followed by
carboxymethylation for example with chloroacetic acid or sodium
chloroacetate, wherein the average numerical value of the alkylene
oxide units is between 0 and 30, preferably between 0.5 and 10,
particularly between 1 and 8.
[0030] The emulsifier composition comprising component (A) and
component (B) according to the invention should preferably be mixed
equimolar related to the functional groups, wherein the average
degree of alkoxylation of all amine compounds and all carboxylic
acid compounds forming the total mixture should preferably be
between 0.5 and 30, particularly between 1 and 10 and most
preferred greater 1 to 6. The alkoxy groups are either solely
within the amine compounds or within both, the carboxylic acid
compounds and the amine compounds.
[0031] The emulsifier system according to the invention is
preferably soluble at 25.degree. C. in the oil.
[0032] Exemplary emulsifier combinations are listed in the
experimental section, others include:
amine-C18-glycol-(2EO)-ether/lactic acid mixture (MARLAZIN
OL2/lactic acid), oleyl-imidazoline/oxo-alcohol-C9-(2EO-2PO)-ether
carboxylic acid mixture (MARLOWET 5440/MARLOWET 4539),
amine-C18-glycol-(7EO)/coconut oil acid mixture MARLAZIN
T7/2/coconut oil acid) or
oleyl-imidazoline/alcohol-C6-glycol-(3EO-3PO)-ether carboxylic acid
mixture (MARLOWET 5440/MARLOWET 4556).
[0033] Appropriate combination of the emulsifier components (A) and
(B) according to the invention enables oils of different
compositions to be used. Examples of oils forming component (C) are
aliphatic or cycloaliphatic hydrocarbons such as alphaolefins
(LAO), polyalpha-olefins (PAO), internal olefins (IO), diesel,
biodiesel, Fischer-Tropsch distillates, esters, particularly ethyl
and/or methyl-(C12 to C22) fatty acid esters, alcohols, ethers,
acetals, (oligo)amides, (oligo)imides and/or (oligo)ketones, also
triglycerides or mixtures thereof.
[0034] The oil is composed in such manner that it is liquid at
25.degree. C., preferably at 0.degree. C. and most preferably at
-10.degree. C. The drilling fluid resulting from the addition of
the composition according to the invention is stable in the
pH-value range between 4 and 10, preferably between 3 and 11. This
pH range describes stability limits. Above and below these limits,
the emulsion breaks and allows targeted separation of the various
components.
[0035] The invertible drilling fluid emulsion obtained from the
above described emulsifier system may be broken and inverted by
alkalisation with strong caustic solutions such as KOH or NaOH
above pH values of 11 or already at pH values of above 10. In this
case, the anionic emulsifier component is hydrophilised and in this
state it has the properties of an oil-in-water emulsifier. An
inversion may also be achieved by addition of strong acids, for
example, such as HCl or H.sub.2SO.sub.4 below a pH value of 3. In
this case the amine will be protonised and forms a salt with the
corresponding anion of the added acid.
[0036] The conversion is enabled particularly advantageously by
readjusting the pH value of cleaved invert drilling fluid emulsions
in the pH value range between 4 to 10, preferably 3 and 11, in a
homogeneous oil-in-water emulsion (flipping), so that they are able
to be reused as drilling fluid.
[0037] It is possible to reuse a large portion of the drilling
fluid by introducing and adjusting the requisite additives listed
previously for said use. In practice, it results in financial
savings and shorter reconditioning process steps, which presents
significant advantages especially in offshore drilling
operations.
[0038] The invertibility of the drilling fluids according to the
invention enables the penetration of the filter cake and the
wetting of the filter cake particles to be reversed. Solids that
can be wetted with water are essential for the subsequent acid
wash, so that for example the particles of the filter cake can be
dissolved with acid or dispersed, and also makes it easier to carry
out the steps necessary for regenerating the oil-charged drilling
material and subsequent removal, for example cleaning
oil-contaminated solid surfaces with water-based rinsing aids.
[0039] The composition according to the invention further contains
water, forming component (F). The aqueous phase of the drilling
fluid may contain for example weighting agents, fluid-loss
additives, alkali reserves, viscosity regulators, water-soluble and
insoluble salts and the like.
[0040] The drilling fluid according to the invention may contain up
to 70% by weight water, preferably 20 to 40% by weight, for example
30% by weight water, particularly a salt-containing aqueous phase
(brine) is usually used.
[0041] The emulsifier components are adjusted suitably and an
appropriate concentration is used within the limits of this
invention. The drilling fluid according to the invention is capable
to emulsify substantial quantities of water even electrolyte-rich
water, such as e.g. CaCl.sub.2 solutions or brine. This property of
the drilling fluid according to the invention means that it may
also be used to absorb water that settles in the lower region of
the drilled hole caused by the ingress of water, without
interrupting the drilling operation.
[0042] Other additives may also used besides the emulsifier or
emulsifier system, including for example wetting agents, weighting
agents to increase weight or density, "fluid loss" additives to
minimise fluid loss, additives for creating an alkalinity reserve,
for filtration control and/or to control rheological
properties.
[0043] Lime or other alkaline substances may be added to oil-based
drilling fluids in order to create an alkalinity reserve. The
alkalinity reserve serves to maintain the viscosity and stability
of the drilling fluid when the drilling fluid is exposed to
variable external influences. This is particularly important in
areas where acidic gases such as CO.sub.2 or H.sub.2S are
encountered during drilling. In the absence of an alkalinity
reserve, acidic gases can lower the pH value of the drilling fluid
and thus weaken the emulsion stability and undesirably change the
viscosity of conventional drilling fluids. Repair or removal of the
drilling fluid is expensive and therefore undesirable.
[0044] The drilling fluid according to the invention may contain
thickening agents such as clays consisting of bentonite, hectorite,
attapulgite and/or mixtures thereof, particularly such mixtures as
have been rendered organophilic by surface treatment. Surface
treatment may be carried out with quaternary ammonia compounds, for
example, so that the clays are rendered hydrophobic. The clays are
used in a concentration from 1 to 10% by weight. The polar
character of the emulsifying component according to the invention
may reduce the quantity of thickening agent required depending on
the type of the thickening agent in question.
[0045] Additives selected from the group including alkaline and
alkaline earth halides, sulphates, carbonates, hydrogencarbonates,
also hydroxides and iron oxides, create what is known as an
alkalinity reserve.
[0046] For example, in "acid gas drilling" acid gases such as
CO.sub.2 and H.sub.2S may be absorbed. The drilling fluid according
to the invention is stable in the pH value range from 4 to 10,
preferably from 4 to 10, and therefore provides a substantial
alkalinity reserve in the upper pH value range (10 to 10.5). The
density of the drilling fluid may also be modified via the salt
concentration in the water phase.
[0047] Emulsifier components (A) and (B) are preferably used in a
molar ratio related to the respective numbers of the functional
groups (amine or carboxylic acid) from 1:1.5 to 0.5 to 1,
particularly 1:1.2 to 0.8 to 1.
[0048] The pH value of the drilling fluid according to the
invention may be adjusted to pH values above 4. Preferably from 8
to 10.0 or 10 to 10.5 by appropriate mixing of the emulsifying
components (A) and (B) according to the invention, such that the
drilling fluid already has its own alkali reserve.
[0049] At the same time, the emulsifying components (A) and (B)
according to the invention have a corrosion inhibiting effect for
metal surfaces and reduce frictional resistances, thus functioning
as lubricants.
[0050] The invention further relates to a composition (the drilling
fluid) comprising at least components (A) to (F): [0051] (A) one or
more primary, secondary or tertiary alkoxylated amine compounds and
[0052] (B) one or more carboxylic acid compounds selected from one
or more members of the group of monocarboxylic acids,
polycarboxylic acids, polyalkylene glycol ether carboxylic acids of
a monoalcohol and poly-alkylene glycol ether carboxylic acids of a
polyol, [0053] (C) an oil that is fluid at 25.degree. C., and
[0054] (D) one or more thickening agents for thickening the oil or
the oil phase, selected from the group including clays, polymers,
alumina and silica, and [0055] (E) one or more additives selected
from the group including alkaline and earth alkaline halides,
sulphates, carbonates, hydrogencarbonates, also hydroxides and iron
oxides, and [0056] (F) water and optionally wetting agents,
weighting agents to increase weight or density, "fluid loss"
additives to minimise fluid loss and a method for drilling a drill
hole using above composition/drilling fluid comprising the step of
introducing the drilling fluid into the drilled hole during the
drilling operation.
[0057] In this context, the method may further comprise steps
according to which the drilling fluid including the drilled
material (cuttings) is extracted, the drilled material is separated
from the drilling fluid, for example by sieving or centrifuging,
and the cleaned drilling fluid is reintroduced into the drilled
hole, optionally after the addition of components such as those
described in the preceding, which have been depleted in the
drilling fluid during the drilling operation.
[0058] The separated drilled material may be treated with an alkali
or an acid solution to break the residual drilling fluid in the
form of a water-in-oil emulsion by adjusting a pH value lower than
3 or higher than 10, particularly higher than 11, and thus obtain
an oil-in-water emulsion as a flushing fluid and a fluid for
removing the oil from the drilled material, in order to obtain a
drilled material even further depleted of the oil.
[0059] Another use of the emulsifier system according to this
invention is the improvement of the cold flow properties of heavy
crude oils and extra heavy crude oils. Heavy crude oils are defined
as any liquid petroleum with an API gravity less than 20.degree..
Extra heavy oil is defined with API gravity below 10.0.degree. API.
In this use the heavy or extra heavy crude oil becomes the oil (C)
or the oil phase of the composition according to the invention. API
is measured according to ASTM D287.
EXPERIMENTAL SECTION
[0060] Various compositions were prepared using the following
components.
25% CaCl.sub.2 solution MISwaco, Houston Barium sulphate M-I BAR,
MISwaco, Houston
Lime Austin White Lime Company, Austin
Mineral oil Gravex 915, Shell
[0061] Wetting agent FM WA II, Fluid Management Ltd. Houston
Polymer thickening agent HRP, MI Swaco, Houston
Quartz Milwhite Inc.
Clay FM VIS LS, Fluids Management, Houston
Example 1
[0062] A diesel-based drilling fluid was prepared at room
temperature from the components listed below, combined in the order
described, having been homogenised beforehand using a Hamilton
Beach overhead mixer on full power for about 40 minutes and being
homogenised within 5 minutes afterwards in a Silverson L4RT mixer
at 3500 rpm. The mixture was evaluated visually taking into account
the precipitation of organic, aqueous and inorganic phases.
TABLE-US-00001 Product Unit 1.1 1.2 1.3 1.4 Diesel % by wt. 28.0
28.0 28.0 28.0 Clay % by wt. 1.0 1.0 1.0 1.0 Polymer thickening
agent % by wt. 0.2 0.2 0.2 0.2 Lime % by wt. 0.7 0.7 0.7 0.7
Emulsifier 1: Oxo-C13-alcohol glycol- % by wt. 1.8 -- -- --
(3EO)-ether (MARLIPAL O13/30) Emulsifier 2: Amine-C18-glycol- % by
wt. -- 1.8 -- -- (2EO)-ether/alcohol C1214-glycol- (3EO)-ether
carboxylic acid mixture (MARLAIN OL2/MARLOWET 4541) Emulsifier 3:
Amine-C18- % by wt. -- -- 1.8 -- glycol-(2EO)-ether (MARLAZIN OL 2)
Emulsifier 4: C1214-glycol- % by wt. -- -- -- 1.8 (3EO)-ether
carboxylic acid (MARLOWET 4541) Wetting agent % by wt. 0.003 0.003
0.003 0.003 25% CaCl2 solution % by wt. 18.3 18.3 18.3 18.3 Barium
sulphate % by wt. 45.0 45.0 45.0 45.0 Quartz % by wt. 5.0 5.0 5.0
5.0 Stability Hrs. <2/<1 >16/>16 <1/<1
<4/<2 Temperature .degree. C. 20/70 20/70 20/70 20/70 (EO =
monomer unit ethylene oxide, PO = monomer unit propylene oxide)
[0063] Example 1 shows that selection of an emulsifier system
consisting of amine-C18-glycol-(2EO)-ether/alcohol
C1214-glycol-(3EO)-ether carboxylic acid enabled stability to be
maintained for >16 hours both at room temperature and at
70.degree. C.
[0064] This could not be achieved using the single components
described as Emulsifier 3 and Emulsifier 4, also not with
Emulsifier 1.
Example 2
[0065] A rapeseed methyl ester-based drilling fluid was prepared as
in example 1. Selection of an emulsifier system consisting of
amine-C18-glycol-(2EO)-ether/alcohol C1214-glycol-(5EO)-ether
carboxylic acid enabled the stability required for this application
to be maintained for >16 hours both at room temperature and at
70.degree. C.
TABLE-US-00002 Product Unit 2.1 2.2 Rapeseed methylester % by wt.
28.0 28.0 Clay % by wt. 1.0 1.0 Polymer thickening agent % by wt.
0.2 0.2 Lime % by wt. 0.7 0.7 Emulsifier 1: Oxo-C13-alcohol-glycol-
% by wt. 1.8 -- (5EO)-ether (MARLIPAL O13/50) Emulsifier 2:
Amine-C18-glycol- % by wt. -- 1.8 (2EO)-ether/alcohol C1214-glycol-
(5EO)-ether carboxylic acid mixture (MARLAZIN OL 2/MARLOWET 1072)
Wetting agent % by wt. 0.003 0.003 25% CaCl.sub.2 solution % by wt.
18.3 18.3 Barium sulphate % by wt. 45.0 45.0 Quartz % by wt. 5.0
5.0 Stability Hrs. <1/<1 >16/>16 Temperature .degree.
C. 20/70 20/70
Example 3
[0066] A rapeseed methyl ester-based drilling fluid was prepared as
in example 1. Selection of an emulsifier system consisting of
amine-C18-glycol-(2EO)/lactic acid enabled the stability required
for this application to be maintained for >16 hours both at room
temperature and at 70.degree. C.
TABLE-US-00003 Product Unit 3.1 3.2 Mineral oil % by wt. 28.0 28.0
Clay % by wt. 1.0 1.0 Polymer thickening agent % by wt. 0.2 0.2
Lime % by wt. 0.7 0.7 Emulsifier 1: Nonyl phenol-glycol- % by wt.
1.8 -- (3EO)-ether (MARLOPHEN NP3) Emulsifier 3: Amine-C18-glycol-
% by wt. -- 1.8 (2EO)/lactic acid mixture (MARLAZIN OL2/lactic
acid) Wetting agent % by wt. 0.003 0.003 25% CaCl.sub.2 solution %
by wt. 18.3 18.3 Barium sulphate % by wt. 45.0 45.0 Quartz % by wt.
5.0 5.0 Stability Hrs. <3/<1 >16/>16 Temperature
.degree. C. 20/70 20/70
Example 4
[0067] A drilling fluid based on paraffin oil (technical,
low-aromatic standard oil) was prepared as in example 1. Selection
of an emulsifier system consisting of
amine-C12-glycol-(2EO)-ether/alcohol-C1618-glycol-(2EO-2PO)-ether
carboxylic acid enabled the stability required for this application
to be maintained for >16 hours both at room temperature and at
70.degree. C.
TABLE-US-00004 Product Unit 4.1 4.2 Paraffin oil % by wt. 28.0 28.0
Clay % by wt. 1.0 1.0 Polymer thickening agent % by wt. 0.2 0.2
Lime % by wt. 0.7 0.7 Emulsifier 1: C18-alcohol-glycol- % by wt.
1.8 -- (5EO)-ether (MARLOWET 5001) Emulsifier 2: Amine-C12-glycol-
% by wt. -- 1.8 (2EO)-ether/Alcohol C1618-glycol- (2EO-2PO)-ether
carboxylic acid mixture (Trial product/MARLOWET 4560 Wetting agent
% by wt. 0.003 0.003 25% CaCl2 solution % by wt. 18.3 18.3 Barium
sulphate % by wt. 45.0 45.0 Quartz % by wt. 5.0 5.0 Stability Hrs.
<3/<1 >16/>16 Temperature .degree. C. 20/70 20/70
Example 5
[0068] In order to study the improvement of cold flow properties of
heavy crude oils and extra heavy crude oils achieved by adding the
emulsifier system and water the following model liquid consisting
of: [0069] MERKUR WOP 240 (Mineral oil with 30% naphthenic bounded
CW and 70% paraffin thereof are 80% iso paraffin and 20%
n-paraffins (C25 to C42), [0070] PARAFOL 22-95 n-Docosan (min 95%),
[0071] PARAFOL 18-97 n-Octadecan (min. 97%), [0072] SASOLWAX 3971
iso paraffin (C24 to C80), microcrystalline wax was used having the
following composition:
TABLE-US-00005 [0072] Model Liquid [% by weight] MERKUR WOP 240 60
PARAFOL 22-95 10 PARAFOL 18-97 5 SASOLWAX 3971 25
Water in Oil--Emulsion Composition:
TABLE-US-00006 [0073] Emulsion [% by weight] C12-C14 2 EO Ether
carboxylic acid + 0.75 Tallow fatty amine 1EO Model Liquid 94.25
Water comprising 10 weight % CaCl.sub.2. 5.0
[0074] The emulsifier is added to the oil phase. Thereafter the
water is added while stirring gently achieving spontaneously an
emulsion showing the following viscosities at different
temperatures.
TABLE-US-00007 Temperature Emulsion Model Liquid [.degree. C.]
[mPas] [mPas] 30 4300 5550 40 1700 2650 50 900 1400 60 350 450
[0075] Viscosity is measured using a Haake Mars 2 cone plate system
(35/2.degree.) at a shear rate of 10/s
* * * * *